Pilot operated valve for controlling the flow of fluids



June 1, 1954 J. J. GERRITSEN ETAL 2,679,856

PILOT OPERATED VALVE FOR CONTROLLING THE FLOW OF FLUIDS 3 Sheets-Sheet 1Filed Jan. 29, 1 951 gmm,

June 1, 19 J. J. GERRITSEN ET AL PILOT OPERATED VALVE FOR CONTROLLINGTHE FLOW OF FLUIDS 3 Sheets-Sheet 2 Filed Jan. 29, 1951 x R mm w m N QHw wt 1 m 4 m i 9v Q WW N\ E fa IIIII Z'IIIIIII/I/II WM 3 ATTORNEi June1, 1954 J. J. GERRITSEN ETAL 2,679,856 PILOT OPERATED VALVE FORCONTROLLING THE FLOW 0F FLUIDS- Filed Jan. 29 1951 3 Sheets-Sheet 3Patented June 1, 1954 EPILOT OPERATED VAL LING THE FLO VE FOR CONTROL- WOF FLUIDS Jacobus Johannes Gerritsen, Redhill Aerodrome, Surrey, andRichard Cox Abel, Hove, Sussex,

England Application January 29, 1951, Serial No. 208,279

5 Claims. 1

.This inventionrelates to poppet-type valves for controlling thefiow of.fiuids. of thekindin which the pressures developed in. the jfiuiditself are utilised to move or hold the ,poppet onto .and

.away from its seating.

A known example of. this general type of valve is the so-called Johnsonvalve .in which the -poppet is. 'operatedby asdevice which constitutesa'double-acting hydraulicram, the two chambers of which are selectablyconnectible the one to the-interior of the valve-cavity, on the upstreamside of the valve-seating, so. as .to.be subjected to'the' pressure of"the "fluid Whose flow is to be controlled, and the other to atmosphere,by means of a :controllableselector valve. According to the position of,thecselector valve, the. pressure of the fluid is-applied to one orother of the ram chambers, the second chamber beingv in each case atatmospheric pressure, so as to cause the poppet-to'seat orunseat asrequired.

The main object-of the presentinvention is to provide a valve of theso-called .dohnsonftype -which will meet the following requirements:

(1) In the open position it must offer no ap- -preciable obstructionto-thefiow, i. e. the loss of 'head through the valve "should be small;

(2) For many applications it 'should'be unaffected by the attitude ofthe valve in space and by accelerations, in any "direction and of anymagnitude, of the body in which the valve is mounted;

(3) 'It must be capable of handling corrosive, inflammable,"poisonous,and otherwise dangerous or destructive fluids;

' (4) It must be immune 'from'lea'kage or discharge "to atmosphere ofthe fluid handled;

(5) It must be capable of satisfactory operation-over a wide range oftemperatures and pressures, including very'high pressures, and underconditions of high flow-rate;

(6) It must be controllable by external means exerting-controllingforces which are-small relatively to the valve-opening and -closingforces;

A further object of the present invention is to regulate the extent towhich the pcppet'leaves its seating and-hence to regulate the rate offlow through-the (main) valveby adjusting the orifice of the pilotvalve, which furnishes in effect an adjustable constriction in theby-pass, whereby the distribution of the pressure drop from the upstreamopening of the passage leading to the ram-chamber to=the downstreamopening of the by-pass can beregulated.

A"further:object of the .present invention is to provide a valve of theso-ca'lled"Johnson type in which the rate of flow through the valve issensitive to variation of throttling of the by-pass and can be closelycontrolled from zero to the maximumcapacity of the valve byadjustment-of .the pilot valve.

A still further object of the present invention is to provide means toensure that the operation of the valve shall be unaffected by itsattitude relative to the earths gravitational field or by accelerations,and to accomplish this, the movable vmember of the cylindrical assemblyconstituted by the poppet and the movable member of the ram unitarytherewith is preferably of the same mass .as the volume of fluidit'displaces, so that when immersed in such fluid said movable member of.the cylindrical assembly isin hydrostatic equi librium.

The manner and means by-which the foregoing objects, and such otherobjects as -may hereinafter appear, maybe achieved will appear from thefollowing description having reference to the accompanying drawingsillustrating two specific embodiments of the invention and amodification done of them by way of example only and without limitationof the scope of the invention as defined in the appended claims. In thedrawings,

Figure 1 is an axial section of an electrically controlled valve;

Figurez is an exploded view ,of-the same valve;

Figure 3 is an axial section of a' manually'controlled valve;

Figure 4 isa sectionon-the line 4- 2 of Figure 3;

Figure 5 isan end elevation of the valve shown in Figures 3 and 4; and

Figure 6 is a View corresponding to a part of Figure 3 and-illustratinga modification.

The valve illustrated in Figures 1 and Zoomprises a valve body composedof two members It and H, said members enclosing a cylindrical cavityhaving hemispherical ends. Member i l fits into member it and is securedin place byan externally threaded collar l2 engaging an internalthreadin the open end of member l9.

Within the cavity of the body formed by members ill and It, is coaxiallylocated a cylindrical assembly with hemispherical ends comprising aram-cylinder it, a ram piston i l, anon-magnetic supporting sleeve 15and a magnet core member 16. -A disc armature I? and an annularcompression springlfi are housed in this assembly.

Axial inlet and outlet tubes :9 and 29 formed, respectively, in themembers is and H, communicate with either end of the valve-cavity whoseotherwise hemispherical ends are made slightly ogival by fairing themargins of the openings of tubes 19 and 20 into the valve-cavity. Themargin of the outlet opening forms a seating 2! for the hemisphericalend 22 of piston 14 constituting the valve poppet; and this margin maybe provided with a seating ring fixedly secured within a groove formedin member H. The direction of fluid flow is indicated by an arrow inFigure l.

The piston 14 is hollow, its cavity 23 constituting an enclosed buoyancychamber, the relation between the volume of this buoyancy chamber andthe total volume of piston i4 being dependent upon the densities of thematerial of which piston i4 is made and or" the fluid which the valve iscontrolling, and usually being predetermined to suit the particularfluid which the valve is intended to control. In the base of piston 14is a boss in which is formed a recess 24 housing a light spring 25,which spring abuts on the head of the ram-cylinder 13.

The sleeve i has three external radial ribs 26, which fit intolongitudinal keyways 2'! in the wall of the cylindrical part of thecavity of member H), and thereby support and locate the cylindricalassembly l3! 6.

The magnet core member is composed of three parts, an outer part 28, aninner part 3! and an end plug 32. The part 28 has a cylindrical portion38, which fits in sleeve 15, and a hemispherical end 29, whose shape iscompleted by plug 32. Parts 23 and 3| are of soft iron and fit togetherto enclose a blind annular space, in which is disposed a solenoid typewinding 33, a spacer ring 34 and the spring !8. Ring 34 is ofnonmagnetic material and hermetically encloses the winding 33. Ring 34also constitutes an abutment for spring I 8, which spring bears on thedisc armature IT and, when unstrained, projects from the pole faces ofthe core parts 28, 3!. The armature l! is of soft iron and fitsslidingly in sleeve !5. It is pierced by a number of holes 39 allowingthe fluid to pass through it, and carries a central ball or needle 40constituting the movable member of the pilot valve.

The inner part 3! is centrally bored to provide an axial passage 35continued by, and communicating with, a constricted axial passage 36 andradial passages 3'! in the end plug 32 terminating in openings 38situated centrally of the upstreamfacing hemispherical end of thecylindrical assembly l3l6.

Integrally formed with the ram cylinder l3, with which it is connectedby integral webs 43 is a ring 4! between which and the cylinder I3 is aninterrupted annular space 42 connecting the interrupted annular passagebetween the member El) and the sleeve is with its continuation betweenmember H and cylinder 13. The ring 4! is clamped between the inner endof member H and a shoulder 48 in member It thus locating the cylinderI3. When the parts are assembled, the webs 43 are aligned with the ribs26 so as to ofier the minimum obstruction to the flow of the fluidthrough the annular passage between the cylindrical assembly l3! 6 andthe walls of the valvecavity.

A radial passage 44 drilled through the ring 4!, one of webs 43 and thehead of cylinder !3 connects a central opening 45 in the cylinder headforming the seating for ball or needle 46 with an opening 46 in the rimof ring 4|, which opening 45 communicates with an annular recess 49formed in member I0. Openings 4'1 in the head of cylinder 13 allow thefluid to enter the cylinder freely from the space between the cylinderhead and the disc armature IT.

The annular recess 49 communicates with a longitudinal groove 50 in thecylindrical outer surface of member H. Groove 56 communicates by meansof a radial passage 5| with an opening 52 in the wall of the outlet tube20 immediately downstream of the poppet seating 21.

The ends of the winding 33 are brought out to the exterior of the valvebody through a radial conduit 53 drilled through the body-member Iii,one of the ribs 26 and the magnet-core part 28 and are thus completelyencased and protected from contact with the fluid in the valve cavity.They are attached to terminals 54 mounted in a terminal block 55 ofinsulating material. Leads 56 are attached to the terminals and one ofthe leads is connected to a control switch diagrammatically indicated at51 in Figure 1.

When the circuit controlled by switch 51 is open, the armature H ismoved by spring (8 away from the magnet pole faces and the ball orneedle 40 seats in the opening 45 and closes the by-pass passage 44, 46,49, 50, 5|, 52. Fluid can enter the ram-cylinder [3 through openings 38,passage 31', 36, 35, holes 39 and openings 41, and so establish in theram-cylinder a pressure equal to that at the inlet of the valve chamber,and, as long as the fluid is in motion, greater than that acting on thepoppet 22 of piston l4 tending to hold it off its seating. The piston I4is therefore moved towards the outlet until its poppet 22 seats on theseating 2| at the margin of the outlet. When the poppet 22 seats andflow stops, the pressure in the ram-cylinder and the pressure acting onthe poppet 22 upstream of the seating 2| are equalised but the projectedarea of the poppet perpendicular to the axis on which it acts is lessthan that of piston l4 in the ram-cylinder, so that the unseating eifortis less than the opposed effort of the ram. The poppet therefore remainsseated.

When the circuit controlled by switch 51 is closed to energise themagnet Hi, the armature I! is attracted to the pole faces and withdrawsthe ball or needle 40 from the opening 45, thus opening the by-pass 44,46, 49, 50, 5!, 52. The pressure at opening 52 being less than at theopenings 38, flow takes place through the bypass, and the constrictionof passage 35 ensures that the drop of pressure between openings 38 andopening 52 is concentrated in passage 36, thus reducing the pressure atthe openings 41 and hence in the ramcy1inder 13, thus reducing theefiort of the ram on the piston l4 sufiiciently for the opposed effortof the external pressures on the poppet 22 to overcome it and unseat thepoppet. When flow through the valve cavity takes place, the pressuresacting on the poppet 22 are reduced relatively to that at openings 38,but now act on the whole area of the poppet, and, as long as the by-passis open, the pressure in the ram cylinder is insufficient to return thepoppet to its seating against the pressures acting on its outer surfacetending to unseat it.

The manually operated valve illustrated in Figures 3, 4, and 5 is ofvery simple construction enabling it to be made cheaply. The bodycomprises three parts, a central part 58 and two end parts 59, 60, heldtogether by through-bolts 6!. The centre part 58 is bored endwise tofurnish a ram-cylinder 53 in which slides a rampiston 64 with ahemispherical end 55 constituting the poppet. The centre part :58 isalso ipierced longitudinally by two slots '66 of-=arcuate cross-section,together constituting :an intervruptedannular passage, and has ahemispherical boss 62 coaxial with and of the same diameter as thepoppet 65 and as the inner wall of the annular passage 66. The innerportion of the part 58 bounded by the annular passage 66, the boss 62and the poppet 65 together constitute a cylindrical assembly withhemispherical ends located coaxially in the cylindrical valve-cavity.

The end parts 159, 6 0 of the body have coaxial inlet andoutlet passages61 and 69, respectively, terminating in hemispherical recesses 68 and"iii of the same maximum diameter 'as the-outer-wall of the annularpassage 66 of the central part 58. The valve-cavity is thereforecylindrical with hemispherical .ends.

The direction of flow is indicated by an arrow in Figure 3.

Theinner rim 88 of the hemispherical recess 10 of the part 60surrounding the opening of the outlet passage 69 constitutes the seatingfor the poppet 65.

The ram-cylinder 63 communicates with a chamber H, from which extends acentral, axial passage 12, continued by and communicating with aconstricted passage 13 through a restrictor 14 in the centre of theupstream-facing hemispherical boss 62 and terminating in an opening 15.

From the chamber ll extends a passage 16, the outer end of which isclosed by a flexible diaphragm 11 whose edge is clamped to the body port58 by a sealing spacer ring 89 secured by a collar 18 internallythreaded to screw onto an external thread on the part 58 and having acentral internally threaded hole receiving an externally threaded stem#9 which can be screwed down onto the diaphragm 11 by means of a handwheel 80.

Coaxially arranged within the passage 16 with a surrounding clearance82, is a tube 8| on whose open end the diaphragm '7'! seats when presseddown by the stem 19. The tube 8! crosses the chamber H and its other endis sealed into the body part 58 and extends to the outer face of thebody where it communicates through a union 83 with an external U-tube84, whose other end communicates through a union B5 and a passage 86 inthe end part 60 of the body with an opening 8'! just downstream of thepoppet seating 88.

The passage 15, tube 8 l, U-tube 84 and passage 86 constitute thebypass, and the diaphragm 11 is the movable member of the pilot valve,whose orifice, furnished by the leakage path between the mouth of tube8i and the diaphragm 11, can be varied by adjusting the stem 19 by meansof the hand-wheel 89, enabling the flow through the main valve to beregulated.

In the modification illustrated in Figure 6, the upper open end of tube3| is counter-bored to provide the conical seating on which a needle 99is seatable. Needle 9% is riveted to a flanged thimble 91, between theflange of which and the top of the threaded portion of the body part 56is trapped a compression spring 93, and whose skirt is guided on a guidetube 52 lodged in a counter-bored recess in the top of the passage 76 inthe body part 58, The needle 96, member 9! and spring 93 are enclosed ina seamless flexible bellows 54 whose closed end rests on the head ofmember 9! and whose skirt is clamped between a taper on the body part 58and an internally tapered clamping ring 95 retained by an internalshoulder :of the threaded cap :18.

Between the end :of the threaded stem 19 :of "the hand-wheel 1:80 and:the closed :end "of :the bellows 94 overlying the :head of member 9! isinserted a mushroom-shapedpadtii.

It .will readily be seen'that adjustment of needle valve 953 withrespect to the open upper end "of .tube 6! is eifected by manipulatingthe handwheel 80, while the bellows 94 furnishesgaifluiw tight sealcompletelyenclosing the needle valve and its associatedseating.

We claim:

v1. A fluid-flow controlling valve comprising .a valve body having a,generally cylindrical cavity with substantially hemispherical ends, an:inlet centrally situated in zone such end and anoutlet centrallysituated in the other such end, the margin of the outlet constituting avalve seating, a generally cylindrical core of greater:diameter than theoutlet, located coaxially in said cavity with surrounding clearance andcomprising a stationary member having a substantially hemispherical endportion directed toward said inlet and an axially movable member havinga substantially hemispherical end portion directed toward and adapted toseat on said valve seating, the stationary member including radialcoresupporting and -locating webs and inner and outer coaxial magneticelements defining a blind annular recess, a solenoid winding in saidrecess, a non-magnetic member sealing the open end of said recess andenclosing the winding, a terminal block on the outside of the body,electrical connections from said winding to said terminal block, saidconnections being enclosed in a radial passage penetrating the outermagnetic element, a radial web and the body, said stationary memberfurther including a fixed apertured diaphragm separating a spaceadjacent the movable member and constituting a ram-chamber from a spacebetween the diaphragm and the magnetic elements, an apertureddisc-armature axially movable in said last-named space, spring loadingmeans tending to move the armature away from the magnetic elements, acentral passage in the inner magnetic element extending from a centralopening in hemispherical end portion of the stationary member to saidlast-named space, a by-pass passage extending from said last-named spacethrough the diaphragm and body to an opening in the outlet downstream ofand contiguous with the valve seating, a pilot-valve member unitary withthe armature, and a pilotvalve seating formed in the diaphragm andcommunicatina with the by-pass passage.

2. A fluid flow controlling valve comprising a valve body having asubstantially cylindrical cavity therein with an inlet opening and anoutlet opening at opposite ends thereof, the wall defining the end ofsaid cavity adjacent the outlet opening being substantiallyhemispherical, the said wall defining said cavity having anaxially-extending passage therethrough extending from a pointsubstantially midway of the length of said cavity to a point downstreamof and contiguous to said outlet opening; a coaxial cylindrical corewithin said cavity with its outer wall spaced inwardly from the walldefining said cavity to provide a flow passage therebetween, said coreincluding a fluid pressure cylinder adjacent the outlet opening of thevalve cavity and having a cylinder head disposed transversely of andsubstantially midway of the length of said cavity and core, said headhaving a passage therethrough with the outer end of said passagecommunicating with said axially-extending passage through said valvebody, said cylinder communicating with the inlet opening of the valvecavity through an orifice located on the axis of said core, and a pistonwithin said cylinder having a substantially hemispherical outer endportion directed toward the outlet opening of the valve cavity, saidsubstantially hemispherical outer end portion of said pistonconstituting a valve for seating on said outlet opening; a bypass fromsaid cylinder including said passage through said cylinder head and saidaxiallyextending passage through said valve body; and a controllablethrottling valve in said bypass for controlling the flow of fluidtherethrough, said orifice being of lesser area than the bore definingsaid bypass.

3. A fluid flow controlling valve as defined in claim 2 in which thecylindrical core is supported within the cavity by circumferentiallyspaced webs extending between the outer surface of said core and thewall defining said cavity.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,141,114 Henderson June 1, 1915 1,961,599 Schwitzer June 5,1934 FOREIGN PATENTS Number Country Date 116,067 Germany Dec. 14, 1900901,783 France Aug. 6, 1943

